Fish nets for culturing, trapping and the like immersed in sea for a long time and materials such as rope and the like supporting these nets, a net for preventing invasion of jellyfishes at an intake port for cooling water, a curtain for the prevention of marine pollution used in seaside working and the like are immersed in sea over a long period of time.
As a result, they are fouled by sessile organisms in sea to cause problems such as clogging of mesh in the net, infection of various fishes with sickness or parasite due to the decrease of flowing quantity of sea water, damage by the increase of weight, decrease of floating force and the like.
As a method of preventing the fouling through such sessile organisms, there has hitherto been widely used an undersea antifouling treating composition containing an organic tin compound such as TBT (tributyl tin compound) or the like as an effective ingredient. However, the tendency of self-control in use or the like is widening from a doubt of storing the effective ingredient in circumstance or the like.
On the other hand, as an antifouling treating composition containing no organic tin compound, there are disclosed a) a technique using a dialkylpolysulfide compound as an effective ingredient in Japanese Patent Application Publication No. 62-43962, and b) a technique on an antifouling treating composition for fish nets containing tetraalkyl thiuram disulfide, dialkylpolysulfide, 2-(thiocyanomethylthio) benzothiazole and the like as an effective ingredient in Japanese Patent laid open No. 60-38306, respectively.
Apart from the above techniques, the inventors have proposed c) a technique on an undersea antifouling treating composition containing a copolymer indicating a particular hydrophilic property and thiocyano alkylthiobenzohetrozole in Japanese Patent laid open No. 1-178562.
However, the effective antifouling performances can not be obtained only by the dialkylpolysulfide compound disclosed as the above technique a, while the tetraalkyl thiuram disulfide, dialkylpolysulfide and 2-(thiocyanmethylthio) benzothiazole disclosed as the above technique b shortly show effective antifouling performances, but it is very difficult to elute a sufficient amount of the effective ingredient from the fish net treating agent over a long period of time. Further, it has been confirmed that only the copolymer indicating the particular hydrophilic property and the thiocycno alkylthiobenzohetrozole previously proposed by the inventors as the above technique c are still insufficient to maintain the effective antifouling performances over a long period of time.
An object of the invention is to provide an undersea antifouling treating composition which can necessarily and sufficiently control the eluting rate of an antifouling agent from the fibrous or rope-like materials immersed in sea over a long period of time.